1. Field of the Invention
The invention relates to video decoding, and more particularly, to apparatuses and related method for decoding a composite video signal according to a clock synchronized to a color burst of the composite video signal.
2. Description of the Prior Art
Since the appearance of the Advanced Television Systems Committee (ATSC) standard, great efforts have been made to perfect a digital TV system. For compatibility, a digital TV system designed for decoding a digital TV signal complying with an ATSC specification must also be able to decode a composite video signal complying with specifications of conventional analog TV systems, such as the National Television System Committee (NTSC) standard or the Phase Alternate Line (PAL) standard. In this way, a user is able to watch programs transmitted by either a digital TV signal or an analog TV signal using the same equipment.
Conventionally, a clock utilized for digitalizing the incoming composite video signal is usually extracted from another clock source not specifically designed to sample the composite video signal. Conventional video decoder may digitize the incoming composite video signal with reference to target line samples, such as 858 samples/line for NTSC standard. Since a chrominance signal is carried on a sub-carrier of the composite video signal, complicated circuits are needed in order to demodulate the chrominance signal.